Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine blade assembly for producing power. Combustors often operate at high temperatures that may exceed 2,500 degrees Fahrenheit. Typical turbine combustor configurations expose turbine blade assemblies to these high temperatures. As a result, turbine blades must be made of materials capable of withstanding such high temperatures. In addition, turbine blades often contain cooling systems for prolonging the life of the blades and reducing the likelihood of failure as a result of excessive temperatures.
Typically, turbine blades are formed from a root portion at one end and an elongated portion forming a blade that extends outwardly from a platform coupled to the root portion at an opposite end of the turbine blade. The blade is ordinarily composed of a tip opposite the root section, a leading edge, and a trailing edge. The inner aspects of most turbine blades typically contain an intricate maze of cooling channels forming a cooling system. The cooling channels in the blades receive air from the compressor of the turbine engine and pass the air through the blade. The cooling channels often include multiple flow paths that are designed to maintain all aspects of the turbine blade at a relatively uniform temperature. However, centrifugal forces and air flow at boundary layers often prevent some areas of the turbine blade from being adequately cooled, which results in the formation of localized hot spots. Localized hot spots, depending on their location, can reduce the useful life of a turbine blade and can damage a turbine blade to an extent necessitating replacement of the blade.
Operation of a turbine engine results is high stresses being generated in numerous areas of a turbine blade. One particular area of high stress is found in the blade's trailing edge, which is a portion of the blade forming a relatively thin edge that is generally orthogonal to the flow of gases past the blade and is on the downstream side of the blade. Because the trailing edge is relatively thin and an area prone to development of high stresses during operation, the trailing edge is highly susceptible to formation of cracks. These cracks may propagate and cause failure of the blade, which may, in some situations, cause catastrophic damage to a turbine engine.
A conventional cooling system in a turbine blade assembly discharges a portion, if not a substantial portion, of the cooling air through a trailing edge of the blade. Typically, the cooling air is discharged through a plurality of openings on the pressure side of the blade. In addition, a cooling system often contains an intricate maze of cooling flow paths in a trailing edge. There exist numerous configurations of the cooling flow paths that attempt to maximize the convection occurring in a trailing edge of a blade. However, uneven heating in trailing edge portions of a turbine blade still often exists.
Thus, a need exists for a turbine blade that effectively dissipates heat in a trailing edge portion of a turbine blade and maintains aspects of the trailing edge portion at the same general temperature.